A white powder found Tuesday in a Georgetown University dorm room tested positive for ricin, school officials said Wednesday, and a D.C. police report indicates that a 19-year-old man told authorities he had produced the substance.

In an e-mail sent campuswide, the university said there was no danger to the community. Law enforcement officials said they did not think that the case was connected to terrorism.

Tests confirmed that a substance removed from a room in McCarthy Hall tested positive for ricin, the university said. The toxin can cause respiratory failure and multi-organ dysfunction, according to the Centers for Disease Control and Prevention.

The police report said the 19-year-old man, whom the report describes as a suspect, “confirmed that he made the substance.”

Amy E. Smithson, a senior fellow with the James Martin Center for Nonproliferation Studies who studies biological weapons, said that when ricin is produced with military precision, the substance can be highly lethal. “Ricin is one of the deadliest substances on the face of the planet, no ifs, ands or buts about it,” she said.

Members of a Joint Terrorism Task Force were on campus Tuesday, the police report said.

Officials tested other areas of the room and the dorm, and the results came back negative. The dorm houses about 290 students. Georgetown has hired specialists to clean the room, the school said.

“There is no immediate threat to members of the Georgetown community,” the e-mail said.

School officials received no reports of anyone being exposed to the toxin, authorities said. D.C. health officials advised the school that symptoms of ricin exposure typically present themselves within 24 hours. “This window has passed and there are no reports consistent with ricin exposure,” the statement said.

FBI spokeswoman Jacqueline Maguire said no arrests had been made as of Wednesday, but officials continued to investigate.

Ricin is a poisonous protein powder made from castor beans, according to the CDC.

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